Telephone system



pn'iE 1942. w. SQHELLER 2,278,593

TELEPHONE SYSTEM 1 Filed March 21, 1959 INVENTOR TO A5 3 'WILHELM SCHELI ER ATTORNEY Patented Apr. 7, 194-2 UNITED STATES PATENT OFFICE hausen, Germany, assignor to schaft fiir die Verwaltung und gewerblichen Schutzrechten Berlin, Germany, a corporation of Haftung, Germany Fides 'Geselli- Verwertung von mit beschrankter Application March 21, 1939, Serial No. 263,277 In Germany March 21, 1938 9 Claims.

The present invention relates to a circuit; arrangement for remote signalling or telephone in stallations in which finder switches have access to high or low valued junction lines. In such systems it is desired that impulses outgoing from high valued junction lines shall have finder switches at their disposal without any appreciable delay.

In previously known arrangements with high and low valued junction lines the situation could arise that when an impulse was transmitted from a high value junction line at a particular moment to the finder switch directly after it had been impulsed from a low valued junction line then the high valued junction would have to wait until the discharge of the low valued call before the finder switch was placed at its disposal.

In the present invention such long waiting periods are avoided. This is arranged by preparing the finder switches over two starting chains arranged one behind the other separated according to the group to which the junction lines belong of which the chain for the high valued call is stepped on independently of the stopping of a finder switch impulsed over the chain for the low valued call as soon as the impulsed finder switch has overrun the contact positions provided for the high valued junction line while the chain for the low valued calling impulse is stepped on immediately on receipt of an impulse over the chain for the high valued impulse.

By this arrangement it is possible to impulse a second finder switch on receipt of an impulse from a high valued junction line while a finder switch impulse by a low valued connection is operat'ng. In this way the original finder switch impulsed from the lower valued connection takes up the impulse transmitted from the high valued set and starts up the second finder switch over the series connection transferring the low valued impulse. Each of these two finder switches can connect the high valued junction line and the finder switch still operating can discharge the low valued connection.

Further by the arrangement according to the invention the further stepping on of the chain for high valued calls is possible previous to the switching through of a finder switch in operation impulsed over the low valued chain in that in those cases in which a finder switch impulsed by a low valued impulse has overrun the contact positions provided for the high valued connections another finder switch is prepared for the v higher valued impulse previous to the stopping of the first operated finder switch.

In the drawing an embodiment of the invention is shown to which however the invention is not limited.

' A subscriber of a high valued junction line is indicated by Th and a subscriber of a low valued junction line by Tn. As many finder switches, such as ASI and A52, are provided for the discharge of calls as may be necessary. These switches are identical, and, as will be seen, are connected in multiple to the subscribers lines so that each has access to all of said lines; they are also connected in series by two impulse circuits, whereby they may be rendered operative in turn, as will now be described. The impulse circuit for the high valued junction lines is indicat-ed by Ahwhile the. impulse circuit for the low valued call impulse is indicated by An. If the subscriber of the set Tn makes a call the relay R2 is energized in the following circuit: earth, contact 2512, the loop of the subscriber Tn, contact 2M2, winding I of relay R2, battery; earth; The relay R2 operates the contacts ZlrZ, and 221-2. By means of contact 2112 the calling subscribers set is' marked in the contact bank of each of the finder switches. Contact 2211 sets upthe following impulse circuit over the circuit An: earth, contact 2,21'2, 23152, distributor V12, contact l6t3, 4113, relay R3, battery, earth. The relay R3 energizes and operates its contacts. Over contact M3 the test circuit for the finder switch A81 is prepared. The contact 113 sets up the following stepping on circuit for the rotary magnet Das: earth, interrupter Un, contact 7T3, wiper d in its zero position, contact Mp3 rotary magnet Das, battery, earth. The interrupter Un connects the rotary magnet whereupon the stepping on circuit is maintained over the wiper d independently of contact 'lr3 until the relay P3 is energized over the line characterized by the contact 2H2. The following circuit is completed whenthe finder switch AS! rests on the calling line: earth, battery, winding II of relay R2, relay T2, contact 2W2, wiper c, windings I and II of relay P3, contact 8r3, earth. In this circuit'the'relays P3 and T2 operate. Relay R2 is maintained energized over the winding II. The contacts mp3 and Mp3 switch through the talking conductors. The contact Mp3 connectsrelay T3 to the outgoing conductor Lc whereupon relay 1T3 operates over a battery not shown; Relay T3 closes contact l5t3 over which the circuit for the relay P3 is maintained after theclosing of contact R503. The

stopping of the finder switch takes place on the openings of l3p3. At contact l6t3 the starting circuit An is stepped on to the next finder switch ASZ. On the operation of the relay T2 the contacts 25t2 and 24f! are operated so that the calling set is connected with the devices beyond the finder switch ASI over the lines La-Lb. By means of contact 23t2 the impulse to the impulse circuit An is interrupted. The relay R3 restores and opens contacts 11-3 and 81*3.

When the party at the subscribers set Tn hangs up his receiver the switching means not shown on the conductors La and Lb restore. In this way the circuit for the relay T3 is interrupted at the conductor L0. The relay T3 restores and over contact l6t3 again makes the finder switch ASI seizable by connection of the relay R3. The relay P3 restores and over the contact l3p3 closes the stepping on circuit for the rotary magnet Das which is held over the wiper d until the finder switch has reached its normal position.

When the finder switch ASI has stepped on over the contact positions provided for the high valued lines during its search for a low valued call, the starting chain Ah is switched on to the next finder switch at the wiper e. Thereafter a high valued call impulse can be transferred directly to finder switch ASZ when the contacts provided for the high valued junction lines have been passed over by switch AS! without the hunting finder switch ASI having to switch through the circuit at contact I'It3 by energizing of relay T3.

If the finder switch AS! is impulsed by means of a low valued junction line over the impulse circuit An, for example from the subscriber of the subscribers line Tn, the following impulse circuit is completed by a high valued subscriber calling at this moment (e. g. Th) earth, contact 2M, 2015!, distributor Vh, wiper e of the finder switch ASI which is hunting, contact Hi3, windings II and I of relay U3, battery, earth. In this circuit relay U3 energizes and operates its contacts. By means of contact 6u3 the winding I of relay U3 is short-circuited so that it now acts as a slow relay. The contact 3113 sets up a holding circuit for the relay R3 energized over the impulse circuit An. The contact u3 maintains the preparation of the test circuit for the relay P3 of the finder switch ASL The contact hi3 connects the starting circuit for the low valued impulse on to finder switch A82 which is reached over the line Ln. Relay R3 in this finder switch now operates owing to the impulse existing for contact 221-2 and therefore starts finder switch ASZ in exactly the same fashion as described above for ASI, so that two finder switches are hunting simultaneously.

It will now be assumed that the original finder switch ASI set into operation by the low valued impulse has reached the calling line of a subscriber Th earlier than the finder switch ASZ impulsed by the operating of contact 411 3. In this case the following circuit is completed for the relays P3 and TI: earth, contact M3, or 8T3, windings II and I of relay P3, wiper 0, contact lrl, relay Tl, winding II of relay RI, battery, earth. In this circuit the relays P3 and TI operate. The relay P3 by opening contact l3p3 stops the rotary magnet Das. The relay Tl operates the contacts |8tl and l9tl so that the subscriber Th is connected with the line La, Lb. The contact lrl is maintained closed since the relay RI is maintained energized over the winding II. The contact 20H is opened so that the relay U3 begins to restore. In the meanwhile however the relay T3 is energized over contact M293 so that the release of the relay U3 at the opening of contact 4u3 does not bring about the switching over to the chain for the low valued connection since the contact l6t3 maintains th switching over. The contact |lt3 switches over the circuit for high valued impulses so that other calling impulses present; on the multiple connection Vh are transmitted over line Lh to subsequently arranged finder switches.

The finder switch ASZ impulsed over the starting circuit An is stepped on until it has found the line marked by the closing of contact 2lr2. When this takes place th relay T2 is energized in series with P3. The latter relay halts the switch ASZ by opening contact I3p3', and at contact 23t2 the impulse is disconnected from the impulse line An. The further setting up of connections over finder switch ASZ takes place in the same manner as has been described in the setting of the finder switch ASI.

What is claimed is:

1. In a telephone system, subscribers lines, finder switches adapted to search for and seize calling ones of said lines, means at times controlled by the initiation of calls from two of said lines in rapid succession for starting a first switch to search for one of the calling lines and starting a second switch to search for the other of the calling lines even before said first switch has found said one line, said means at other times controlled by the initiation of calls from two of said lines in rapid succession for starting a first switch to search for one of the calling lines and then starting a second switch to search for the other of the calling lines only responsive to said first switch finding said one line.

2. In a telephone system, lines of different classes, finder switches having access to said lines, means for operating one of said switches to cause it to search for a calling one of said lines, and means controlled by the initiation of a call from another of said lines while said o erated sw1tch is still searching for said one line for initiating the operation of another of said switches either before or after said one switch finds said one line depending upon the class of said one 3. In a telephone system, lines of different classes, finder switches having access to said lines, means for operating one of said switches to cause it to search for a calling one of said lines, and means controlled by the initiation of a call from another of said lines while said operated switch is still searching for said one line for inihating the operation of another of said switches either before or after said one switch finds said one line depending upon the class of said other 4. In a telephone system, lines of different classes, finder switches having access to said lines, means for operating one of said switches to cause it to search for a calling one of said lines, and means controlled by the initiation of a call from another of said lines while said operated switch is still searching for said one line for inihating the operation of another of said switches either responsive to said one switch finding said one line or independently of said one switch finding said one line, depending upon the class of said one line.

5. In a telephone system, lines of different classes, finder switches having access to said aaraeos lines, means for operating one of said switches to cause it to search for a calling one of said lines, and means controlled by the initiation of a call from another of said lines while said operated switch is still searching for said one line for initiating the operation of another of said switches either responsive to said one switch finding said one line or independently of said one switch finding said one line, depending upon the class of said other line.

6. In a telephone system, lines of different classes, finder switches having access to said lines, means for operating one of said switches to cause it to search for a calling one of said lines, means controlled by the initiation of a call from another of said lines while said one switch is still searching for said one line for initiating the operation of another of said switches responsive to said one switch finding said one line if said one line and said other line are of the same class, and means controlled by the initiation of a call from another of said lines while said one switch is still hunting for said one line for initiating the operation of another of said switches independently of said one switch finding said one line if said one line and said other line are of diiferent classes.

7. In a telephone system, two groups of lines, finder switches having access to said lines,

a finder start circuit common to the lines of one 3 group, a second finder start circuit common to the lines of the second group, means responsive to a call from any line for applying potential to the start circuit common to the group of which the calling line is one, means thereupon operated over said start circuit by said potential to start one of said switches to search for said calling line, means for transferring one of said start circuits to another switch while said one switch is still searching for the calling line, thereby to condition said other switch to operate before said one switch finds said calling line in the event a subsequent call is originated in one group of lines While said one switch is still searching, and means for transferring the other of said start circuits to said other switch only responsive to said one switch finding said calling line, thereby to prevent said other switch from operating before said one switch finds said calling line in the event a subsequent call is originated in the other group of lines while said one switch is still searching.

8. A telephone system as claimed in claim 7, wherein the start circuit transferred to said other switch while said one switch is still searching extends over a wiper of said one switch.

9. In a telephone system, a plurality of subscn'bers lines, a plurality of finder switches having access to said lines, and means operated over a wiper of One of said switches responsive to one of said lines initiating a call for at times starting said one switch to search for the calling line and at other times starting another of said switches to search for the calling line, whereby a connection from a calling one of said lines may be completed over either of said switches.

WILHELM SCHEILER. 

